Process of refining sugar



UNITED STATES OTTO ALEXANDER BIELMANN,

PATENT OFFICE.

or NEW ORLEANS, LOUISIANA.

PROCESS OF REFINING SUGAR.

SPECIFICATION forming part of Letters Patent No. 557,643, dated April 7, 1896,

Application filed March 29, 1895.

To all whom it may concern:

Be it known that I, Orro ALEXANDER BIEL- MANN, a subject of the Emperor of Germany, residing at New Orleans, in the parish of Orleans and State of Louisiana, have invented new and useful Improvements in Processes of Refining Sugars, of which the following is a specification.

My invention relates to the art of manufacturing sugar from cane, beet, and all sugarcontaining plants, the purpose of my invention being to improve upon the methods of manufacturing sugar in common use at this time, and to obtain more sugar of better quality which shall be ready for direct consumption, the same being produced in one continuous operation. The followingis a full description of my process and will serve to make it understood by all who are familiar with the manufacture of sugar.

It is a well-known fact that the method of clarifying raw-sugar solutions (I refer mostly to raw juice obtained from either sorghum or sugar-eane)'is an empirical one and removes and alters certain classes of the none-sugars present in said solution to'a very limited extent. These are known as albuminoids, such as arabinose or pectinose, &c., on one side and glucose on the other side, which are eliminated, as stated hereinbefore, only to a very limited extent by the methods in co1nmen use. Yhile neither phosphoric acid (H PO nor pyrophosphorie acid (ILP O is able to eliminate these organic none-sugars named, metaphosphoric acid (I-IPO and its salts eliminate the greater part of those impurities by coagulation, and thus purify the sugar solutions to a great extent. Therefore I apply a small amount of this acid compound to said sugar-containing solution in any suitable stage of the sugar n1 anufaeturethat is to say, I use said acid by mingling the same with the raw juice as soon as the latter is 0b tained (either by the crushing-mill or by the diffusion process) or I may use said acid after the raw juice is more or less evaporated or at any point where said juice maybe termed syrup. I may also apply itin the vacuumpan, mixer, or centrifugal machine wherever circumstances make it preferable to do so. I prefer to use said acid by mixing it with the sugar-containing solution after the raw Serial No. 543,708. (No specimens.)

j uice is first extracted either by the crushingmill or by the diffusion or other process, and before any lime is added, because of the'fact that it only shows the peculiarity of coagulating the above-named compounds when the acid is used in a free state. \Vherever this clarifying agent may be used, however, I prefer to remove the eoagulations which are formed as soon as possible, which may be done either by skimming, filtering, or decanting.

Owing to the fact that in the course of clarifying, evaporating, and reboiling some organic compounds, not fully explored and described as yet, show a greater tendency to coagulate than they show in the first stage of manufacture, I apply a very small amount even to after products, or to first, second, and third molasses, in order to restore the graining capacity to the highest possible point, as more .fully described in my application for Letters Patent filed upon the 21st day of J uly, 1894, Serial No. 518,2 2.

There are two ways to render the glucose present in saturated or supersaturated sugar solutions crystallizable, the first being to form crystallizable anhydrous glucose crystals by adding a few crystals of anhydrous glucose itself, the second being to form a compound known as sodium ehlorid glucose (also termed glucosate of sodium chlorid) having (after l'liebig) the formula NaCl2C II O 2110. As both crystalline compounds are formed only in saturated or supersaturated solutions, it naturally has to be done in the vacuum-pan, and to do this I use in both cases a few crystals of both anhydrous glu cose or sodium-chlorid glucose, either compound being used, as preferred. The introduction of said compounds may be made in various ways, but I prefer to mix said crystals with sugar crystals of a suitable size and add the mixture to the sugar solution, the purpose bcing in order to start crystallization of both glucose and sucrose at the same time. Thiscourse is also desirable because of the fact that being mixed thoroughlyin this mannor the proportion between the sugar crystals and the crystals of glucose or sodium-chlorid glucose will always be substantially in the desired proportion; If it should be desirable to form the sodium-chlorid glucose compound, I first determine by analysis the amount of glucose, sodium, and chlorin that may be present in a certain lot of syrup, sufficient in quantity to make a strike of first masse-cuite. I prepare, in accordance with the analysis, enough of sodium and chlorin (it being sufiicient, under normal conditions, to use sodium chlori'd for said purpose) to bind all the glucose present in a givenquantity of syrup by forming sodium chlorid glucose in the manner stated above. Said solution, which must, be as highly concentrated as possible, is also mixed with the sugar crystals and the crystals added thereto of sodium chlorid glucose already mentioned. After this has been done the whole mixture is drawn into the vacuum-pan in the usual way.

In order to get the best possible crystallization of both sugar and sodium-chlorid glucose crystals, it is advisable to boil the strike down to a moisture test of between five per cent. and seven per cent. and, after the finished masse-cuite is dropped in the mixer, to add a suitable amount of a sugar solution of about from five to ten per cent. of the massecuite,showing about the same purity as the uncrystallizable part of said strike, or, in other Words, the first molasses will show this added sugar solution having a density of about 36 or 38 Baum, will be mixed with the massecuite quickly, and will in the process of centrifugal drying carry through the meshes of the centrifugal sieve the much smaller crystals of sodiumchlorid glucose, where they may be separated either by filtration or decantation.

In order to get rid of the coloring-matter, which, when present, forms a material feature in manufacturing high-grade sugar, I proceed as follows: Instead of using sulfurous-acid gas, as is done in almost all sugarfactories where they make this class of sugar, I may also use hyposulfurous acid, having a formula of H 80 or it's salts, in which is dissolved a very small quantity of indigo-blue,-

thus converting the indigo-blue to indigowhite by reduction. sugar solution to a far better extent, when treated inthis manner, than is obtainable by the use of sulfurous-acid gas alone, but I form certain compounds with the coloring-matter of the so-treated sugar-containing juice by the use .of hydrosulfurous acid or its salts, insoluble in the sugar-containing solution,

which can be removed in the usual way. I

prefer to use this bleaching reagent in all the stages of the sugar manufacture where it may be applied profitably; but I prefer to use the same for the most part, as already set forth, on raw juice as soon as the same is separated from the sugar-containing plant, and as long as said juice is in a cold state, and to adda verysmall quantity of the compound again in the evaporation stage, and finally either in the vacuum-pan or mixer or centrifugal machine, together with the wash, (generally water and discoloring compounds.)

I not only bleach the In order to avoid melting of the sugar crys-' tals, as is done by the use of water to agreat extent, I prepare the wash out of sugar-syrup having a density of 25 Baum and mix-with about one-tenth of one per cent. of hy'posulfurous acid. I apply said wash only after all molasses has separated from the sugar crystals. This wash, being of a high purity, may

-be caught separate in the general manner.

The indigo-blue mixed with said acid is reduced to indigo-white, and, passing through the Whole process of manufacture, will gradually be reconverted into indigo-blue by oxidation taking place wherever the sugar solution or masse-cuite or sugar crystals are exposed to the atmosphere, thus giving the sugar crystals the desired colorless appearance, which will stay and not fade or deteriorate after a very short time, as is the case in the use of any bluing now in common use.

It must be clearly understood that I may use indigo-blue or its equivalent for the purpose described in combination with any'acid compound or chemical reagent which will effect similar results.

WVhat I claim is- 1. In the manufacture of crystallizable sugar, the process hereinbefore described which consists in mingling with the sugarcontaining solution, at any stage in the process of manufacture, a suitable proportion of metaphosphoric acid or its salts in a free state, whereby the elimination and removal of organic bodies is efiected, substantially as described.

2. In the manufacture of sugar, the process herein described, for the elimination of glucose'which consists in the crystallization of said glucose by adding to the sugar solution crystallized glucose, or a crystallized salt of glucose, such for'ins tance, as sodium chlorid glucose, substantially as described. 3. In the manufacture of sugar, the process hereinbefore described, which consists in boiling the strike down to a suitable density,

and then adding a mixture of sugar crystals and anhydrous crystals ofthe type of sodiumchlorid glucose, whereby the crystallization of sucrose and glucosebegins simultaneously, substantially as described.

4. In the manufacture of sugar, the process described consisting in the simultaneous promotion of crystallization both of sucrose and glucose, by adding to a saturated or supersaturated sugar solution containing glucose, while being boiled to masse-cuite in the vacuum-pan, amixture containing sugar crystals of a suitable size, with crystals of anhydrous glucose or the type of sodiumchlorid glucose, substantially as described.

5. In the manufacture of sugar, the process herein described, which consists in adding a small percentage of indigo-white to the sugaroontaining juice and again adding a further portion thereof to the sugar solution in the vacuum-pan, substantially as described.

6. In the manufacture of crystallizable sugar, the process hereinbefore described for decoloring .the sugar .crystals, said process consisting in adding to the rawsugar-containing'juic'e and tolthe "sugar solutions subsequently derived, therefrom, hyposulfurous acid (H SO or asalt thereof-, bleaching and crystallizing the coloring n1atter thereby and separating the same from the solution in the form-of an insoluble compound, substantially as described.

7'. -In themanufactnre of sugar, the method described which consists in incorporating with a sugar solution; hyposulfurous acid (H550 or a 'saltofsaid acid in which is dis; solved a small amount of' a decoloring com pound, such for example as indigo-white, in order to bleach the sugar-containing solution and-to remove .coloring matterpre'sent in said solution by forming crystals, which are elinii-'v nated'inthe usual way at the" same timeby the presence of the indigo-white in the sugar solutions before' boiling into" masse=;cuite,

every grainiofsaid solution thus containing some of said decoloring compound which will improve theiappearanceof -the dried sugar crystals and by being gradually oxidized to serve said color, substantially as described.

8. The process described for manufacturing first mingling with the sugar-containing solution at any stage a suitable quantity of metaphosphoric acid,.or itssalts, to remove organic impurities, second eliminating the glucose by salt of glucose such as sodium-chlorid glucose, third adding to the sugar-containing juice a small quantity of indigo-white,fourth bleachingthe sugar'crystals by adding to the soluthereof', and fifth converting the indigo-white into indigo-blue by the gradual oxidation of the crystals by the atmosphere, substantially as described.

my hand in presence of two subscribing witnesses. a

- orr'o' ALEXANDER .BIELMANN.

lVi'tnesses: JAMES L. NORRIS, Tnos. A. GREENI.

indigo-blue by atmospheric oxygen, will pre- I sugar which consists in the following steps; 30

adding .to the solution glucose crystals, or a 35 tion hyposulfurousacid (H 50 or a salt 40 In testimony whereof I have hereunto set 45 

